The present invention relates to an integrated circuit for being arranged between a source of higher voltage and a source of lower voltage, including reference current sources and an analog/digital converter with a resistor ladder connected between a terminal called top terminal and a terminal called bottom terminal for producing a series of reference voltages, the bottom terminal being connected to the source of lower voltage via a variable voltage element.
Such a circuit is used when one seeks to quantify an analog voltage, for example, in medical imaging in the domain of oscilloscopes and digital communication, notably television.
An analog/digital converter such as mentioned above is known from patent abstract JP-A-58-25717. In the analog/digital converter described in this document, the bottom terminal is connected to the source of lower voltage via an element that introduces a variable offset voltage, and for providing the influence of the fluctuation of this offset voltage, the high voltage is produced by a fixed voltage source connected to the bottom terminal.